The present invention relates to an electrical hand-held power tool, in particular a hammer drill and a saw. The hand-held power tool is attached to an electrical network for the supply of power via a supply cable. In the case of improper operation, a tool—e.g., a chisel—may sever the supply cable.
The hand-held power tool, according to the invention, has a tool receptacle, an electric motor which drives the tool receptacle, and machine housing. A two-part supply cable has a first section, which is mechanically fastened inside the machine housing, and a second section, which is coupled to the first section outside the machine housing by a detachable plug connection. The detachable plug connection has a locking mechanism, which is locked so that it can rotate around an axis and unlocks along the axis in the case of a tensile load above a limit value.
The plug connection constitutes a mechanical weak point in the supply cable. Due to the possibility of rupturing the plug connection, care must be taken in this case that no stranded wires or current-carrying contacts are exposed. As a result, the plug connection is provided with an overload protection, which forcibly opens the plug connection in a controlled manner in the event of a corresponding tensile load. The limit value for the tensile load is preferably greater than a weight force of the hand-held power tool, which is typically between 30 N and 300 N. In an emergency, an operator is able to lift the hand-held power tool by the supply cable without the plug connection disconnecting.
The locking mechanism has a rotating mechanism for manual locking and unlocking. The different actuation direction of the rotating mechanism, compared to the forcible unlocking triggered along the axis, decouples the rotating mechanism from the forcible unlocking. As a result, the closure mechanism is able to be actuated by an operator with a low expenditure of force. The second section of the supply cable is able to be replaced without great expense.
One embodiment provides that a first half of the locking mechanism contains a peg. A second half of the locking mechanism contains a connecting member guiding the peg. The connecting member connects two openings that point in the direction of the first half of the locking mechanism and are arranged offset in the circumferential direction. A spring-loaded barrier element engages in the connecting member. The peg is able to be introduced in the case of the one opening without an expenditure of force and be pushed using a rotary movement toward the back of the barrier element. The barrier element prevents the peg from being able to exit from the second opening in case of a low tensile force. The connecting member may have a route running monotonically along the axis between the second opening and the spring-loaded barrier element. When the barrier element is disengaged because of a great tensile force, it is possible for the peg to be pulled free along the monotonic route up to the second opening because of the tensile force. One embodiment provides that the connecting member have a further route from the first opening to the spring-loaded barrier element, wherein the further route has a change in direction with respect to the axis. In the case of applied tensile force, the peg is pulled to the barrier element and not to the first opening. If an operator wants to disengage the closure mechanism, he/she must first move the peg against the tensile force to the change in direction and then rotate it in the direction of the first opening.
A route section of the connecting member running parallel to the circumferential direction ends adjacent to the spring-loaded barrier element. This route section prevents the peg from running back to the first opening when a tensile force is applied.
One embodiment provides that the one plug connection half include a sleeve, from which the peg projects radially, and the other plug connection half includes a sleeve, in which the connecting member is configured as a groove countersunk in the radial direction. The sleeves are mutually rotatable. Moreover, the sleeves may enclose an electrical contact area.
One embodiment provides that the electrical contact area includes a socket with a first electrical contact and a plug with a second electrical contact, wherein the first contact is open in the circumferential direction for receiving the second contact. The electrical connection is established at the same time as the rotation to close the closure mechanism, or the electrical connection is interrupted with the rotation to unlock the electrical connection. An angular alignment of the first contact with respect to the peg may be equal to an angular alignment of the second contact with respect to the one opening of the connecting member.
The following description explains the invention on the basis of exemplary embodiments and figures.